The present invention relates to a motor and a disk drive apparatus including the motor.
In recent years, motors wherein current paths are alternated electronically with plural transistors have been used widely as drive motors for office automation apparatuses and audio-visual apparatuses. These motors are included in disk drive apparatuses, such as optical disk drive apparatuses (DVD apparatuses, CD apparatuses, etc.) and magnetic disk drive apparatuses (HDD apparatuses, FDD apparatuses, etc.). A motor wherein current paths to windings are alternated with PNP power transistors and NPN power transistors is available as an example of the above-mentioned motors.
FIG. 26 shows a conventional motor, and its operation will be described below. A rotor 2011 has a field part formed by a permanent magnet. Three position detecting elements of a position detector 2041 detect the magnetic field of the field part of the rotor 2011. In other words, the position detector 2041 generates two sets of voltage signals, Kp1, Kp2 and Kp3, and Kp4, Kp5 and Kp6, from the three-phase output signals of the three position detecting elements in response to the rotation of the rotor 2011. A first distributor 2042 generates three-phase low-side signals Mp1, Mp2 and Mp3 responding with the voltage signals Kp1, Kp2 and Kp3 respectively to control the activation of the low-side NPN power transistors 2021, 2022 and 2023 shown in FIG. 26. A second distributor 2043 generates three-phase high-side signals Mp4, Mp5 and Mp6 responding with the voltage signals Kp4, Kp5 and Kp6 respectively to control the activation of the high-side PNP power transistors 2025, 2026 and 2027 shown in FIG. 26. As a result, three-phase drive voltages are supplied to windings 2012, 2013 and 2014.
In the conventional configuration, power loses of the power transistors are large, and heat generation at the motor and the disk drive apparatus causes problems. The NPN power transistors 2021, 2022 and 2023 and the PNP power transistors 2025, 2026 and 2027 supply drive voltages having desired amplitudes to the windings 2012, 2013 and 2014 by controlling the voltage across the emitter and the collector in an analogue manner. Each of the NPN power transistors 2021, 2022 and 2023 and the PNP power transistors 2025, 2026 and 2027 changes the voltage across the emitter and the collector depending on the change in the resistance value across the emitter and the collector. Therefore, a remaining voltage in each power transistor is large, and a large power loss produced by the product of the large remaining voltage and the conducted current is generated, resulting in heat generation at each power transistor. Since a recordable disk (a RAM disk, a rewritable disk, etc.) is susceptible to heat, the heat generation at the power transistors, i.e., the main heat sources of the disk drive apparatus, is desired to be reduced as low as possible in order to improve the reliability of recording and/or-reproducing on/from the recordable disk.
In addition, since the position detector 2041 includes three position detecting elements for detecting the rotational position of the rotor 2011 so as to distribute drive currents to the windings, it is necessary to provide spaces for the position detecting elements. Furthermore, wire connection and the like for the elements become complicated, thereby raising the cost of the motor and the apparatus. By eliminating the position detecting elements, the motor can be made smaller, and the disk drive apparatus can be made thinner.
Furthermore, in the case of rewritable disk drive apparatuses, such as DVD-RAM/RW apparatuses, information is recorded and/or reproduced on/from a high-density disk. Therefore, it is desired to rotate the disk with reduced vibration during recording and/or reproducing on/from the disk. Moreover, it is necessary to rotate the disk at high speed with reduced acoustic noise in the case of reproducing from a DVD-ROM/CD-ROM disk. However, in a configuration without a position detecting element, it is very difficult to rotate the rotor and the disk with a low vibration and a low acoustic noise while reducing heat generation.
It has been strongly desired to develop a motor and/or a disk drive apparatus in which each of or all of these problems are solved. It is therefore an object of the present invention to solve the above-mentioned problems, respectively or concurrently and provide a motor and/or a disk drive apparatus that has the configuration suitable for reducing the power consumption and the acoustic noise.
A motor in accordance with the present invention comprises:
a rotor which has a field part generating field fluxes;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means which includes two output terminals for supplying a DC voltage;
power supplying means having Q first power transistors and Q second power transistors for supplying a power to the Q-phase windings, each of the Q first power transistors forming a current path between one output terminal side of the voltage supplying means and one of the Q-phase windings, and each of the Q second power transistors forming a current path between the other output terminal side of the voltage supplying means and one of the Q-phase windings;
voltage detecting means for producing a detected pulse signal;
state shifting means for shifting a holding state from one state to at least one other state in sequence responding with the detected pulse signal of the voltage detecting means;
activation control means for controlling active periods of the Q first power transistors and the Q second power transistors responding with the holding state; and
switching operation means for causing at least one of the Q first power transistors and the Q second power transistors to perform high-frequency switching corresponding to a command signal;
and that
the activation control means produces Q-phase first activation control signals and Q-phase second activation control signals responding with said holding state of said state shifting means for controlling the active periods of the Q first power transistors and the Q second power transistors, each of the active periods being an electrical angle larger than 360/Q degrees,
the switching operation means produces a switching pulse signal responding with the command signal, and makes high-frequency switching operation of at least one power transistor among the Q first power transistors and the Q second power transistors responding with the switching pulse signal, and
the voltage detecting means stops detecting of the detected pulse signal during at least one of a first stop period including a changing timing from OFF to ON of the at least one power transistor and a second stop period including another changing timing from ON to OFF of the at least one power transistor, and executes detecting of the detected pulse signal during at least ON period of the at least one power transistor excluding the at least one of the first stop period and the second stop period, thereby producing the detected pulse signal responding with terminal voltages of the Q-phase windings. With this configuration, the switching operation means subjects the power transistors of the power supplying means to high-frequency switching. Therefore, power loses at the power transistors of the power supplying means can be reduced significantly, and heat generation at the motor can also be reduced greatly. In addition, the voltage detecting means produces the detected pulse signal responding with the terminal voltages of the windings, and the state shifting means shifts the phases of the activation to the windings in response to the detected pulse signal. Furthermore, the activation control means activates the power transistors responding with the holding state so as to rotate the rotor in a predetermined direction. Therefore, no position detecting element is required, and the configuration of the motor is simplified. Moreover, each of the active periods of the first power transistors and the second power transistors is made larger than an electrical angle of 360/Q degrees. Therefore, two power transistors among the first power transistors or the second power transistors are activated simultaneously in an alteration of current paths. The alteration of current paths is thus smoothened, and the generated drive force has less pulsation. As a result, the vibration and the acoustic noise of the motor can be reduced. In addition, the power transistor/transistors is/are subjected to high-frequency switching operation by using the switching pulse signal. The detection of the detected pulse signal is stopped at least one of the first stop period including the changing timing from OFF to ON of the power transistor and the second stop period including the other changing timing from ON to OFF of the power transistor. Therefore, it is possible to prevent improper detection owing to high-frequency noises in the terminal voltages caused by the high-frequency switching operation of the power transistor/transistors. In addition, the detection of the detected pulse signal in response to the result of the comparison of the winding terminal voltages is performed during at least the ON period of the power transistor excluding at least one of the above-mentioned stop periods. It is therefore possible to produce the detected pulse signal promptly responding with the comparison result of the terminal voltages. In other words, it is possible to obtain the detected pulse signal accurately responding with the terminal voltages. Therefore, the alteration of current paths to the windings can be performed at accurate timing in response to the detected pulse signal of the voltage detecting means, and the rotor can be rotated smoothly and accurately. Furthermore, in the case when speed control is performed in response to an output pulse signal such as the detected pulse signal of the voltage detecting means for example, the rotational speed of the rotor can be controlled accurately. In other words, it is possible to attain an accurate rotation of the motor without an influence of high-frequency switching noises in the terminal voltages. As a result, an excellent motor without a position detecting element can be realized, which reduces the power consumption, the motor vibration and the acoustic noise, according to the present invention.
A motor in accordance with another aspect of the present invention comprises:
a rotor which has a field part generating field fluxes;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means which includes two output terminals for supplying a DC voltage;
power supplying means having Q first power transistors and Q second power transistors for supplying a power to the Q-phase windings, each of the Q first power transistors forming a current path between one output terminal side of the voltage supplying means and one of the Q-phase windings, and each of the Q second power transistors forming a current path between the other output terminal side of the voltage supplying means and one of the Q-phase windings;
voltage detecting means for producing a detected pulse signal;
state shifting means for shifting a holding state from one state to at least one other state in sequence responding with the detected pulse signal of the voltage detecting means;
activation control means for controlling active periods of the Q first power transistors and the Q second power transistors responding with the holding state; and
switching operation means for causing at least one of the Q first power transistors and the Q second power transistors to perform high-frequency switching corresponding to a command signal;
and that
the activation control means produces Q-phase first activation control signals and Q-phase second activation control signals responding with said holding state of said state shifting means for controlling the active periods of the Q first power transistors and the Q second power transistors, each of the active periods being an electrical angle larger than 360/Q degrees,
the switching operation means produces a switching pulse signal responding with the command signal, and makes high-frequency switching operation of at least one power transistor among the Q first power transistors and the Q second power transistors responding with the switching pulse signal, and
the voltage detecting means includes:
voltage comparing means for producing an output signal responding with comparison result of terminal voltages of the Q-phase windings, and
noise eliminating means for gating the output signal of the voltage comparing means with a noise eliminating signal responding or corresponding with the switching pulse signal, so as not to pass the output signal of the voltage comparing means during at least one of a first period including a changing timing from OFF to ON of the switching pulse signal and a second period including another changing timing from ON to OFF of the switching pulse signal.
With this configuration, the switching operation means subjects the power transistors of the power supplying means to high-frequency switching. Therefore, power loses at the power transistors of the power supplying means can be reduced significantly, and heat generation at the motor can also be reduced greatly. In addition, the voltage detecting means produces the detected pulse signal responding with the terminal voltages of the windings, and the state shifting means shifts the phases of the activation to the windings in response to the detected pulse signal. Furthermore, the activation control means activates the power transistors responding with the holding state so as to rotate the rotor in a predetermined direction. Therefore, no position detecting element is required, and the configuration of the motor is simplified. Moreover, each of the active periods of the first power transistors and the second power transistors is made larger than an electrical angle of 360/Q degrees. Therefore, two power transistors among the first power transistors or the second power transistors are activated simultaneously in an alteration of current paths. The alteration of current paths is thus smoothened, and the generated drive force has less pulsation. As a result, the vibration and the acoustic noise of the motor can be reduced. Furthermore, the voltage detecting means comprises the voltage comparing means and the noise eliminating means. In the noise eliminating means, the output signal of the voltage comparing means is logically gated with the noise eliminating signal which is responding with the switching pulse signal. In particular, the output signal of the voltage comparing means is nullified during at least one of the first period including the changing timing from OFF to ON of the switching pulse signal and the second period including the changing timing from ON to OFF of the switching pulse signal. Therefore, it is possible to produce the detected pulse signal free from an influence of noise due to the high-frequency switching operation of the power transistors. Furthermore, since the detected pulse signal responding with the output signal of the voltage comparing means is produced, it is possible to obtain the detected pulse signal promptly responding with the comparison result of the winding terminal voltages. Therefore, the alteration of current paths to the windings can be performed at accurate timing in response to the detected pulse signal of the voltage detecting means, and the rotor can be rotated smoothly and accurately. Furthermore, in the case when speed control is performed in response to an output pulse signal such as the detected pulse signal of the voltage detecting means for example, the rotational speed of the rotor can be controlled accurately. In other words, it is possible to attain an accurate rotation of the motor without an influence of high-frequency switching noises in the terminal voltages. As a result, an excellent motor without a position detecting element can be realized, which reduces the power consumption, the motor vibration and the acoustic noise, according to the present invention.
A motor in accordance with another aspect of the present invention comprises:
a rotor which has a field part generating field fluxes;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means which includes two output terminals for supplying a DC voltage;
power supplying means having Q first power transistors and Q second power transistors for supplying a power to said Q-phase windings, each of said Q first power transistors forming a current path between one output terminal side of said voltage supplying means and one of said Q-phase windings, and each of said Q second power transistors forming a current path between the other output terminal side of said voltage supplying means and one of said Q-phase windings;
voltage detecting means for producing a detected pulse signal;
state shifting means for shifting a holding state from one state to at least one other state in sequence responding with the detected pulse signal of said voltage detecting means;
activation control means for controlling active periods of said Q first power transistors and said Q second power transistors responding with said holding state; and
switching operation means for causing at least one of said Q first power transistors and said Q second power transistors to perform high-frequency switching corresponding to a command signal;
and that
said state shifting means shifts said holding state from a first state to a second state after a first adjust time from detection of said detected pulse signal, and further shifts said holding state from said second state to a third state after a second adjust time from detection of said detected pulse signal, said second adjust time being larger than said first adjust time,
said activation control means produces Q-phase first activation control signals and Q-phase second activation control signals responding with said holding state of said state shifting means for controlling said active periods of said Q first power transistors and said Q second power transistors, each of said active periods being an electrical angle larger than 360/Q degrees, and
said switching operation means includes:
current detecting means for producing a current detected signal responding with or corresponding to a current from said voltage supplying means to said Q-phase windings, and
switching control means for comparing an output signal of said current detecting means with said command signal and producing a switching pulse signal responding with the comparison result, thereby making high-frequency switching operation of at least one power transistor among said Q first power transistors and said Q second power transistors responding with said switching pulse signal.
With this configuration, the switching operation means subjects the power transistors of the power supplying means to high-frequency switching. Therefore, power losses at the power transistors of the power supplying means can be reduced significantly, and heat generation at the motor can also be reduced greatly.
In addition, the voltage detecting means produces the detected pulse signal responding with the terminal voltages of the windings, and the state shifting means shifts the phases of the activation to the windings in response to the detected pulse signal.
Furthermore, the activation control means activates the power transistors responding with the holding state so as to rotate the rotor in a predetermined direction. Therefore, no position detecting element is required, and the configuration of the motor is simplified.
In addition, the state shifting means shifts the holding state from a first state to a second state after a first adjust time from detection of said detected pulse signal, and further shifts the holding state from the second state to a third state after a second adjust time (the second adjust time greater than the first adjust time) from detection of the detected pulse signal. The activation control means produces Q-phase first activation control signals and Q-phase second activation control signals responding with the holding state of the state shifting means for controlling the active periods of the Q first power transistors and the Q second power transistors. With this configuration, each of the active periods of the Q first power transistors and the Q second power transistors is made larger than an electrical angle of 360/Q degrees. Furthermore, the switching operation means controls the supply current to the Q-phase windings from the voltage supplying means in correspondence with the command signal by making high-frequency switching operation of at least one power transistor among the Q first power transistors and the Q second power transistors. With this configuration, two power transistors among the Q first power transistors or the Q second power transistors are activated simultaneously in each alteration of current paths while the at least one power transistor performs the high-frequency switching operation so as to control the supply current responding with the command signal.
Therefore, the supply current to the Q-phase windings is controlled responding with the command signal even when the two power transistors are activated simultaneously, and the pulsation of the generated drive force can be reduced. Furthermore, the alteration of current paths is thus smoothened by the simultaneous activation of the two power transistors, the pulsation of the generated drive force can further be reduced. As a result, an excellent motor without a position detecting element can be realized, which reduces the power consumption, the motor vibration and the acoustic noise, according to the present invention.
The switching operation means can be configured so as to include current detecting means for obtaining a current detected signal responding with the supply current to the Q-phase windings from the voltage supplying means, and switching control means for comparing the output signal of the current detecting means with the command signal and producing a switching pulse signal responding with the comparison result, thereby making high-frequency switching operation of at least one power transistor among the Q first power transistors and the Q second power transistors responding with the switching pulse signal. With this configuration, it is easy to control the supply current to the Q-phase windings responding with the command signal even when the two power transistors among the Q first power transistors or the Q second power transistors are activated simultaneously during an alteration of current paths.
The state shifting means can be configured so as to change the first adjust time and the second adjust time in response to an interval of the detected pulse signal. With this configuration, each of the active periods of the Q first power transistors and the Q second power transistors is easily made larger than 360/Q degrees (the period can be held at 130 degrees or more for example) even if the rotational speed of the rotor changes widely.
A disk drive apparatus in accordance with the present invention comprises:
a head for at least reproducing a signal from a disk or recording a signal on a disk;
processing means for at least processing an output signal from the head and outputting a reproducing information signal, or processing a recording information signal and outputting a signal into the head;
a rotor which has a field part generating field fluxes, and directly drives the disk;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means which include two output terminals for supplying a DC voltage;
power supplying means having Q first power transistors and Q second power transistors for supplying a power to the Q-phase windings, each of the Q first power transistors forming a current path between one output terminal side of the voltage supplying means and one of the Q-phase windings, and each of the Q second power transistors forming a current path between the other output terminal side of the voltage supplying means and one of the Q-phase windings;
voltage detecting means for producing a detected pulse signal;
state shifting means for shifting a holding state from one state to at least one other state in sequence responding with the detected pulse signal of the voltage detecting means;
activation control means for controlling active periods of the Q first power transistors and the Q second power transistors responding with the holding state; and
switching operation means for causing at least one of the Q first power transistors and the Q second power transistors to perform high-frequency switching corresponding to a command signal;
and that
the activation control means produces Q-phase first activation control signals and Q-phase second activation control signals responding with said holding state of said state shifting means for controlling the active periods of the Q first power transistors and the Q second power transistors, each of the active periods being an electrical angle larger than 360/Q degrees,
the switching operation means produces a switching pulse signal responding with the command signal, and makes high-frequency switching operation of at least one power transistor among the Q first power transistors and the Q second power transistors responding with the switching pulse signal, and
the voltage detecting means stops detecting of the detected pulse signal during at least one of a first stop period including a changing timing from OFF to ON of the at least one power transistor and a second stop period including another changing timing from ON to OFF of the at least one power transistor, and executes detecting of the detected pulse signal during at least ON period of the at least one power transistor excluding the at least one of the first stop period and the second stop period, thereby producing the detected pulse signal responding with terminal voltages of the Q-phase windings.
With this configuration, the switching operation means subjects the power transistors of the power supplying means to high-frequency switching. Therefore, power loses at the power transistors of the power supplying means can be reduced significantly, and heat generation at the disk drive apparatus can also be reduced greatly. In addition, the voltage detecting means produces the detected pulse signal responding with the terminal voltages of the windings, and the state shifting means shifts the phases of the activation to the windings in response to the detected pulse signal. Furthermore, the activation control means activates the power transistors responding with the holding state so as to rotate the disk in a predetermined direction. Therefore, no position detecting element is required, and the configuration of the disk drive apparatus is simplified. Furthermore, each of the active periods of the first power transistors and the second power transistors is made larger than an electrical angle of 360/Q degrees. Therefore, two power transistors among the first power transistors or the second power transistors are activated simultaneously in an the alteration of current paths. The alteration of current paths is thus smoothened, and the generated drive force has less pulsation. As a result, the disk drive apparatus has a low vibration and a low acoustic noise. In addition, the power transistor/transistors is/are subjected to high-frequency switching operation by using the switching pulse signal. The detection of the detected pulse signal is stopped at least one of the first stop period including the changing timing from OFF to ON of the power transistor and the second stop period including the other changing timing from ON to OFF of the power transistor. Therefore, it is possible to prevent improper detection owing to high-frequency noises in the terminal voltages caused by the high-frequency switching operation of the power transistor/transistors. In addition, the detection of the detected pulse signal in response to the result of the comparison of the winding terminal voltages is performed during at least the ON period of the power transistor excluding at least one of the above-mentioned stop periods. It is therefore possible to produce the detected pulse signal promptly responding with the comparison result of the terminal voltages. In other words, it is possible to obtain a detected pulse signal accurately responding with the terminal voltages. Therefore, the alteration of current paths to the windings can be performed at accurate timing in response to the detected pulse signal of the voltage detecting means, and the disk can be rotated smoothly and accurately. Furthermore, in the case when speed control is performed in response to an output pulse signal such as the detected pulse signal of the voltage detecting means for example, the rotational speed of the disk can be controlled accurately. In other words, it is possible to attain an accurate rotation of the disk without an influence of high-frequency switching noises in the terminal voltages. As a result, an excellent disk drive apparatus can be realized, which reduces the power consumption, the disk vibration and the acoustic noise, according to the present invention.
A disk drive apparatus in accordance with another aspect of the present invention comprises:
a head for at least reproducing a signal from a disk or recording a signal on a disk;
processing means for at least processing an output signal from the head and outputting a reproducing information signal, or processing a recording information signal and outputting a signal into the head;
a rotor which has a field part generating field fluxes, and directly drives the disk;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means which includes two output terminals for supplying a DC voltage;
power supplying means having Q first power transistors and Q second power transistors for supplying a power to the Q-phase windings, each of the Q first power transistors forming a current path between one output terminal side of the voltage supplying means and one of the Q-phase windings, and each of the Q second power transistors forming a current path between the other output terminal side of the voltage supplying means and one of the Q-phase windings;
voltage detecting means for producing a detected pulse signal;
state shifting means for shifting a holding state from one state to at least one other state in sequence responding with the detected pulse signal of the voltage detecting means;
activation control means for controlling active periods of the Q first power transistors and the Q second power transistors responding with the holding state; and
switching operation means for causing at least one of the Q first power transistors and the Q second power transistors to perform high-frequency switching corresponding to a command signal;
and that
the activation control means produces Q-phase first activation control signals and Q-phase second activation control signals responding with said holding state of said state shifting means for controlling the active periods of the Q first power transistors and the Q second power transistors, each of the active periods being an electrical angle larger than 360/Q degrees,
the switching operation means produces a switching pulse signal responding with the command signal, and makes high-frequency switching operation of at least one power transistor among the Q first power transistors and the Q second power transistors responding with the switching pulse signal, and
the voltage detecting means includes:
voltage comparing means for producing an output signal responding with comparison result of terminal voltages of the Q-phase windings, and
noise eliminating means for gating the output signal of the voltage comparing means with a noise eliminating signal responding or corresponding with the switching pulse signal, so as not to pass the output signal of the voltage comparing means during at least one of a first period including a changing timing from OFF to ON of the switching pulse signal and a second period including another changing timing from ON to OFF of the switching pulse signal.
With this configuration, the switching operation means subjects the power transistors of the power supplying means to high-frequency switching. Therefore, power loses at the power transistors of the power supplying means can be reduced significantly, and heat generation at the disk drive apparatus can also be reduced greatly. In addition, the voltage detecting means produces the detected pulse signal responding with the terminal voltages of the windings, and the state shifting means shifts the phases of the activation to the windings in response to the detected pulse signal. Furthermore, the activation control means activates the power transistors responding with the holding state so as to rotate the rotor in a predetermined direction. Therefore, no position detecting element is required, and the configuration of the disk drive apparatus is simplified.
Furthermore, each of the active periods of the first power transistors and the second power transistors is made larger than an electrical angle of 360/Q degrees. Therefore, two power transistors among the first power transistors or the second power transistors are activated simultaneously in an alteration of current paths. The alteration of current paths is thus smoothened, and the generated drive force has less pulsation. As a result, the vibration and the acoustic noise of the disk drive apparatus can be reduced.
Furthermore, the voltage detecting means comprises the voltage comparing means and the noise eliminating means. In the noise eliminating means, the output signal of the voltage comparing means is logically gated by the noise eliminating signal which is responding with the switching pulse signal. In particular, the output signal of the voltage comparing means is nullified during at least one of the first period including the changing timing from OFF to ON of the switching pulse signal and the second period including the changing timing from ON to OFF of the switching pulse signal. Therefore, it is possible to produce the detected pulse signal free from an influence of noise due to the high-frequency switching operation of the power transistors.
Furthermore, since the detected pulse signal responding with the output signal of the voltage comparing means is produced, it is possible to obtain the detected pulse signal promptly responding with the comparison result of the winding terminal voltages. Therefore, the alteration of current paths to the windings can be performed at accurate timing in response to the detected pulse signal of the voltage detecting means, and the disk can be rotated smoothly and accurately. Furthermore, in the case when speed control is performed in response to an output pulse signal such as the detected pulse signal of the voltage detecting means for example, the rotational speed of the disk can be controlled accurately. In other words, it is possible to attain an accurate rotation of the disk without an influence of high-frequency switching noises in the terminal voltages. As a result, an excellent disk drive apparatus can be realized, which reduces the power consumption, the disk vibration and the acoustic noise, according to the present invention.
A disk drive apparatus in accordance with another aspect of the present invention comprises:
a head for at least reproducing a signal from a disk or recording a signal on a disk;
processing means for at least processing an output signal from said head and outputting a reproducing information signal, or processing a recording information signal and outputting a signal into said head;
a rotor, which has a field part generating field fluxes, and directly drives said disk;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means, which includes two output terminals for supplying a DC voltage;
power supplying means having Q first power transistors and Q second power transistors for supplying a power to said Q-phase windings, each of said Q first power transistors forming a current path between one output terminal side of said voltage supplying means and one of said Q-phase windings, and each of said Q second power transistors forming a current path between the other output terminal side of said voltage supplying means and one of said Q-phase windings;
voltage detecting means for producing a detected pulse signal;
state shifting means for shifting a holding state from one state to at least one other state in sequence responding with the detected pulse signal of said voltage detecting means;
activation control means for controlling active periods of said Q first power transistors and said Q second power transistors responding with said holding state; and
switching operation means for causing at least one of said Q first power transistors and said Q second power transistors to perform high-frequency switching corresponding to a command signal;
and that
said state shifting means shifts said holding state from a first state to a second state after a first adjust time from detection of said detected pulse signal, and further shifts said holding state from said second state to a third state after a second adjust time from detection of said detected pulse signal, said second adjust time being larger than said first adjust time,
said activation control means produces Q-phase first activation control signals and Q-phase second activation control signals responding with said holding state of said state shifting means for controlling said active periods of said Q first power transistors and said Q second power transistors, each of said active periods being an electrical angle larger than 360/Q degrees, and
said switching operation means includes:
current detecting means for producing a current detected signal responding with or corresponding to a current from said voltage supplying means to said Q-phase windings, and
switching control means for comparing an output signal of said current detecting means with said command signal and producing a switching pulse signal responding with the comparison result, thereby making high-frequency switching operation of at least one power transistor among said Q first power transistors and said Q second power transistors responding with said switching pulse signal.
With this configuration, the switching operation means subjects the power transistors of the power supplying means to high-frequency switching. Therefore, power losses at the power transistors of the power supplying means can be reduced significantly, and heat generation at the motor can also be reduced greatly.
In addition, the voltage detecting means produces the detected pulse signal responding with the terminal voltages of the windings, and the state shifting means shifts the phases of the activation to the windings in response to the detected pulse signal.
Furthermore, the activation control means activates the power transistors responding with the holding state so as to rotate the rotor in a predetermined direction. Therefore, no position detecting element is required, and the configuration of the disk drive apparatus is simplified.
In addition, the state shifting means shifts the holding state from a first state to a second state after a first state adjust time from detection of said detected pulse signal, and further shifts the holding state from the second state to a third state after a second adjust time (the second adjust time  greater than the first adjust time) from detection of the detected pulse signal. The activation control means produces Q-phase first activation control signals and Q-phase second activation control signals responding with the holding state of the state shifting means for controlling the active periods of the Q first power transistors and the Q second power transistors. With this configuration, each of the active periods of the Q first power transistors and the Q second power transistors is made larger than an electrical angle of 360/Q degrees. Furthermore, the switching operation means controls the supply current to the Q-phase windings from the voltage supplying means in correspondence with the command signal by making high-frequency switching operation of at least one power transistor among the Q first power transistors and the Q second power transistors. With this configuration, two power transistors among the Q first power transistors or the Q second power transistors are activated simultaneously in each alteration of current paths while the at least one power transistor performs the high-frequency switching operation so as to control the supply current responding with the command signal.
Therefore, the supply current to the Q-phase windings is controlled responding with the command signal even when the two power transistors are activated simultaneously, and the pulsation of the generated drive force can be reduced. Furthermore, the alteration of current paths is thus smoothened by the simultaneous activation of the two power transistors, the pulsation of the generated drive force can further be reduced. As a result, an excellent disk drive apparatus without a position detecting element can be realized, which reduces the power consumption, the disk vibration and the acoustic noise, according to the present invention.
The switching operation means can be configured so as to include current detecting means for obtaining a current detected signal responding with the supply current to the Q-phase windings from the voltage supplying means, and switching control means for comparing the output signal of the current detecting means with the command signal and producing a switching pulse signal responding with the comparison result, thereby making high-frequency switching operation of at least one power transistor among the Q first power transistors and the Q second power transistors responding with the switching pulse signal. With this configuration, it is easy to control the supply current to the Q-phase windings responding with the command signal even when the two power transistors among the Q first power transistors or the Q second power transistors are activated simultaneously during an altration of current paths.
The state shifting means can be configured so as to change the first adjust time and the second adjust time in response to an interval of the detected pulse signal. With this configuration, each of the active periods of the Q first power transistors and the Q second power transistors is easily made larger than 360/Q degrees (the period can be held at 130 degrees or more for example) even if the rotational speed of the rotor changes widely.
These and other configurations and operations will be described in detail in the explanations of embodiments according to the present invention.
While the novel features of the invention are set forth particularly in the appended claims, the invention, both as to organization and content, will be better understood and appreciated, along with other objects and features thereof, from the following detailed description taken in conjunction with the drawings.